Outline2 - 1 Outline 2 Introduction to the Nervous System...

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Unformatted text preview: 1 Outline 2 Introduction to the Nervous System I. Major Players: Neurons & Glia A. 1. Neurons ("nerve cells") - cells that receive information and transmit it to other cells by conducting electrochemical impulses -Approximately 100 billion neurons in the adult human brain -Each neuron forms 10's to millions of connections with other neurons -The sites of these connections are synapses (aka synaptic connections ) 2. Glia (aka "neuroglia" for nerve glue, aka glial cells ) about 10X's as many glial cells as neurons in brain and they occupy approximately the same amount of space as neurons a. Macroglia 1. astrocytes 2. oligodendrocytes (CNS) 3. Schwann cells (PNS) b. Microglia - brain macrophages- immune function B. Very Basics of Neurons 2 (1) Basic structure of the neuron dendrites dendritic spines (some neurons) cell body (aka soma, sing., somata, plura) axon initial segment of axon (aka, axon hillock) axonal arbors (aka axonal ramifications, axonal branches) nodes of Ranvier-- found in myelinated axons axonal boutons, varicosities and "terminals" "en passant" terminals myelin sheath (some neurons) (2) Major microstructure nucleus-contains chromatin (chromosomes-long strands of DNA)--transcription (RNA/ "gene expression") (translation -> new proteins) mitochondria-energy producers (oxidative metabolism) cytoplasm-"gel" containing a matrix of filaments making up the cytoskeleton: microtubules-largest filaments--participate in trasport of substances within the cells 2 (1) Basic structure of the neuron dendrites dendritic spines (some neurons) cell body (aka soma, sing., somata, plura) axon initial segment of axon (aka, axon hillock) axonal arbors (aka axonal ramifications, axonal branches) nodes of Ranvier-- found in myelinated axons axonal boutons, varicosities and "terminals" "en passant" terminals myelin sheath (some neurons) (2) Major microstructure nucleus-contains chromatin (chromosomes-long strands of DNA)--transcription (RNA/ "gene expression") (translation -> new proteins) mitochondria-energy producers (oxidative metabolism) cytoplasm-"gel" containing a matrix of filaments making up the cytoskeleton: microtubules-largest filaments--participate in trasport of substances within the cells 3 neurofilaments- found in axons but not dendrites microfilaments-finest filaments polyribosomes-packets of ribosomes (RNA and proteins) that synthesize proteins. Polyribosomes are found either free in the cytoplasm, in aggregates ("polyribosomal aggregates") or studding endoplasmic reticulum Golgi bodies- packaging of substances into vesicles (3) Membranes Lipid bilayer studded with proteins -these proteins form channels and receptors II. Directions: dorsal-ventral rostral-caudal (anterior-posterior) medial-lateral Planes: sagittal/coronal/horizontal 4 III. Major Parts of the Nervous System A. Divisions of the Nervous System 1. Central Nervous System (CNS) a. Brain b. Spinal Cord- communicates with sense organs and muscles below the head -segmented structure. -segmented structure....
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Outline2 - 1 Outline 2 Introduction to the Nervous System...

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